Wireless receiving circuit



.Feb. 19, 1929. 1,702,439

' N. P. HINTON WIRELESS RECEIVING CIRCUIT Filed May '7, 1924 WITNESSES: INVENTOR r ATTOR NEY Patented Feb. 19, 1929.

UNITED STATES PATENT OFFICE.

NORMAN P. HINTON, OF LONDON, ENGLAND, .ASSIGNOR, BY MESNE ASSIGNMENTS, TO METROPOLITAN-VICKERS ELECTRICAL COMPANY LIMITED, A BRITISH JOINT STOCK COMPANY.

Application filed May 7, 1924, Serial No. 711,556, and in Great Britain June 27, 1923.

My invention relates to wireless receiving apparatus and, more particularly, to wireless receiving apparatus containing regenerating means and means for preventing re-radiation.

Oneobject of my invention is to provide a regenerative radio receiving apparatus in which special circuits are provided for preventing the transfer of regenerative energy to the aerial circuit.

Another object of my invention is to pro vide a radio receiving apparatus having a double inductive transferring means whereby energy may be transferred from an aerial circuit to a detector circuit; means whereby the detector circuit may be regenerated and means whereby the transfer of energy to the aerial circuit from the detector circuit is pre vented.

Another object of my invention is to pro-- vide a radio receiving system having a plurality of radio frequency transformers and a feed back transformer in connection with a triode detector and a system of connections whereby the regenerative effect of the feed back transformer is confined to the secondary circuits of the coupling transformers.

Another object of my invention is to provide a circuit with a three-electrode vacuum tube detector and other apparatus, so arranged in connection with an aerial circuit, that regeneration may be employed from the anode circuit of the detector tube without causing oscillations in the antenna circuit.

In the prior art of the reception of radio signals, it has been customary to use a threeelement vacuum tube as a signal detector. This detector has customarily been supplied with energy from a tuned aerial circuit, and with auxiliary energy from a high voltage battery. and it has been customary to provide feedback means whereby energy is transferred from the anode circuit of the tube to the grid circuit thereof. In operation, it has been found that such a system is frequently adjusted in such way that an excess amount of energy was transferred from the anode circuit to the grid circuit, and from the grid circuit to the aerial circuit. thereby setting up oscillations in the aerial circuit and reradiating radio frequency energy, thereby producing serious interference with adjacent receiving stations.

My invention provides a means whereby en ergy can be fed back from the anode circuit to the grid circuit thereby giving the desin able feed-back action and increasing the sensitivity and response of the device, and it further provides means whereby energy fed back from the anode circuit to the grid circuit is prevented from being transferred to the aerial circuit, thereby removing the tendency to set the aerial into oscillation and likewise removing the tendency to re-radiate the undesired energy.

Further objects and structural details of my invention will be apparent from the following description when read in connection with the accompanying drawing, wherein:

The single figure is a diagrammatic view of circuit and apparatus embodying my invention.

In the drawing, an aerial is shown at 1 in series with a fixed condenser 2, and having an adjustable condenser 3 in parallel with the inductances. The high frequency transformers 4 and 5 have their respective primary windings 6 and 8 connected in series in; the same sense in the aerial circuit to form the aerial. inductance. The two secondary windings 7 and 9 are connected in series in the same sense and their free ends connected through two condensers 10 and 11 which are mechanically coupled so as to be simultaneously and similarly adjustable. The junction of the two secondary coils is connected to the conductor joining the common plate of the condensers 10 and 11., through an inductance 12 of which. the value is small compared with that of the two secondary coils of the transformers.

The two plates of the condenser 10 in the oscillatory circuit thus formed are connected as shown to a three-electrode valve. One plate is connected to the grid 13 of the valve 14 through a condenser 15 which is shunted by a grid leak 16. The other plate of the condenser 10 is connected to the filament 17 of the valve. The circuit from the anode 18 of the valve comprises an inductance 19 in series with telephones 20 and a high tension battery 21.

The two inductance coils 19 and 12 are electromagnetically coupled so that reaction is introduced between the anode and grid circuits of the valve.

In the apparatus arranged in this manner, when a signal is being received from the aerial into the coupled secondary circuits, the circuit including the tuning condensers 10 and 11 mid the secondary windings '7 and 9 of the transformers will respond to the signal oscillation, the currents in the neutral wire and inductance coil 12 being equal and opposite. When reaction is applied by means of the coupling between coils 19 and 12, the reaction electromotive force tends to increase the total signal response in the circuit 7, 10, 12 and to decrease it in circuit 9, 11, 12. By a slight readjustment of the mechanically coupled tuning condensers 10 and 11, the maximum response in circuit 7, 10 and 12 can be obtained for the amount of reaction applied.

If, however, the reaction should be pushed so far that the circuits connected to the valve oscillate, this oscillation will not be radiated from the aerial for the following reason: Since the tuning condensers are mechanically coupled, the two oscillatory circuits formed by the inclusion of the inductance 12 in the main oscillatory circuit always remain substantially similar and the electroniotive force in the two secondary coils of the transformer due to the valve oscillations are substantially equal and opposite so that no resultant effect is transferred to the primary windings. Consequently, oscillations generated in the circuit when no signals are being received are perfectly balanced in their effect on the aerial and the only oscillations radiated from the aerial will. be those due to signals being received which are radiated as is well known in every case.

It is to be understood that various modiiications in the circuit arrangements, such as the substitution of mechanically coupled condensers, can be made without departing iron the scope of the invention.

While I have shown only one embodiment of my invention in the accompanying drawing, it is capable of various changes and modifications without departing from the spirit thereof and it is desired, therefore, that only such limitations shall be imposed thereon. as are indicated in the prior art or in the appended claims.

v claim as my invention:

In a radio receiving system, a receiving circuit, two similar circuits inductively and similarly related thereto, a vacuum-tube apparatus operatively associated with said similar circuits and including a feed-back device symmetrically related to said similar circuits and delivering energy thereto in such a direction that the inductive actions of said similar circuits upon the receiving circuit are in opposed senses, whereby the energy circuit, two similar circuits inductively and similarly related thereto, a vacuum-tube apparatus operatively associated with said sim ilar circuits and including a feed-back device symmetrically related to said similar circuits, whereby the energy delivered to said similar circuit by said feed-back device is without effect upon said receiving circuit, said similar circuits each including an adjustable tuning means and mechanical connections for simul* taneously adjusting said tuning means to cause said similar circuits to accord with the degree of feed back.

3. In a radio receiving system, a regenerative detector comprising a vacuum tube having a plate circuit provided with a tickler coil, a net work energized from said tickler coil, said net work including two series-tuned paths in parallel and a grid circuit comprising connections from the grid and filament, respectively, to separated points of said net work.

a. Radio-frequency receiving apparatus comprising a thermionic device having a fila" ment, a grid and a plate, an inductor, a pair of simultaneously adjustable series condensers connected in effective shunt thereto, means associating said condensers whereby the ad justment of one is accompanied by the adjustment of the other, a connection between an intermediate point on said inductor to the common point of said condensers, a connection between said common point and said filament, a lead from one end of said inductor to the grid of said device,and means whereby energy may be transferred from said plate to the connection between said inductor and said common point, whereby said thermionic device may be utilized regeneratively in the reception of signals without causing the radiation of energy.

5. Radio-frequency receiving apparatus comprising a thermionic device having a lilainent, a grid and a plate, an inductor, a pair of series condensers connected in shunt thereto and interconnected for simultaneous actuation, an energy receptor circuit inductively associated with said inductor, a lead. from one end of said inductor to said grid, a lead from an. intermediate point on said inductor to the common point of said condensers, an inductor serially included in said lead, a lead from said common point to said filament, and means for inductively associating said plate with said last-mentioned inductor, whereby said thermionic device may be utilized regeneratively in the reception of signals without causing the re-radiation of energy therefrom into said energy-receptor circuit.

In testimony whereof, I have hereunto subscribed my name this fourteenth day of April,

NORMAN P. HINTON. 

